I just finished the book and have a different interpretation to offer. I am pretty convinced this is a somewhat convoluted interpretation but I wanted to see what other readers have to think about this.
After reading the book, I immediately went to have a listen of the Beatles' Norwegian Wood, having never heard it before. With the large number of allusions made to the song, it appears to me that the book could be interpreted in the manner it parallels the song.
Unless I'm mistaken, the song was about a boy who was invited into the room of a girl and misled into believing that sex was on offer when the girl really wanted to talk. When the possibility of that went down the drain after a talk that lasted till 2am, the boy ended up spending the rest of the night sleeping in the bathtub. On waking and finding that the girl had left without even bothering to wake him up, he decided to light a fire and burn the girl's Norwegian Wood (the furniture she had been proud of).
In a similar but different way, Toru was after something from Naoko. He was looking to obtain Naoko's love and Naoko used the knowledge to get what she wanted from Toru - a chance for emotional closure and companionship. There are suggestions that she believed that she could only obtain these from Toru as they were part of the trio and only Toru would be able to understand what she had gone through and how she felt. Through his reminiscing in Chapter 1, we also find out that Toru came to the realisation, albeit eventually, that Naoko did not love him (perhaps only not enough to live for him and face the hardships of the real world). So Toru goes to Ami Hostel with the hope of healing Naoko and winning her love, and gets used by Naoko in the process, with the consequence that he forsakes his growing passion for Midori for entire stretches of time.
It seems to be no coincidence that Ami Hostel is located in a secluded part of the countryside and hidden in the woods (apparently, the woods in Norwegian Woods originally referred to forests in Japanese). And it was introduced to Toru, and he comes to be convinced of it as well, as being better that the outside world in some ways. Just as the girl in the original song showed her room and asked "isn't it good, Norwegian Wood?"
When Naoko eventually did leave by committing suicide, Toru was devastated and hit rock bottom. He spent one month roaming around before he finally "woke up" Of course, he doesn't truly wake up until he meets Reiko and talks things through with her.
The parallels seem feasible to me until this point where I feel I might be stretching it a little...
Toru obviously doesn't light a fire and burn up the woods as an act of revenge. However, he ended his associations with Ami Hostel when Reiko left. We are told he had sex with Reiko four times, ending a long period of time without sex for him as a result of his love for Naoko. The act of sexual intercourse itself might be seen as an act of defiance and revenge but why Reiko? It might be that Reiko, who had spent 8 years in Ami Hostel, was symbolically a representation of not just the place, but of all the emotional drama that had occurred there. Just as Naoko says of sex on the night before her suicide, that '[she] never wanted to be violated like that again - by anybody', Toru was defiling the memories of the occurrences in the woods through the sexual acts.
If this interpretation is followed, it then follows that the entire episode between Toru and Naoku is finally over from unfulfilled promises and manipulations to revenge. While it has come to a conclusion, Toru is not necessarily free from the effects of the incident - it will probably colour his view and his attitude just as Kizuki's death weighed over his life. Nonetheless, Toru had closed a chapter of his life since Kizuki's death that caused him to close himself off, and he was reborn without a disabling baggage. He finally calls Midori from the phone booth and tells her, "I have to talk to you. I have a million things to talk to you about. A million things we have to talk about. All I want in this world is you. I want to see you and talk. I want the two of us to begin everything from the beginning." Toru had overcome an invisible barrier between Midori and him that had caused him to be closed off about his history with Naoku and to be stuck in terms of his relationship with Midori (perhaps this is shown by Toru's limits to his sexual acts with Midori, never progressing beyond what he had already done with Naoku). We get the sense that there is a chance that this time, there can finally be progress.
And if I'm allowed to squeeze this last analysis out, the last puzzling scene gives us another clue...
"Where was I now? I had no idea. No idea at all. Where was this place? All that flashed into my eyes were the countless shapes of people walking by to nowhere. Again and again I called out for Midori from the dead centre of this place that was no place."
In a way, it seems like Toru had been living an extended dream and that he had finally opened his eyes to the world around him. He had no idea where he was. He was in a senseless world and that he was surrounded by people with irrational thoughts and motivations. Toru knew that he was an outsider and with all the chaos of the normal world around him he could not understand, he only knew that he wanted - needed - Midori to survive.
